Taking traditional photographs of molecules is impossible because molecules are smaller than the wavelength of visible light. So scientists have to use higher energy (smaller wavelength) ways of imaging the impossibly small -that’s where the electron microscope comes in. But the problem with bombarding something with high energy electrons is it can destroy the very thing you’re trying to look at, especially something as fragile as DNA. But never say never – scientists at University of Genoa, Italy finally worked out a method to capture an image of the life-encoding molecule.
It’s the most famous corkscrew in history. Now an electron microscope has captured the famous Watson-Crick double helix in all its glory, by imaging threads of DNA resting on a silicon bed of nails. The technique will let researchers see how proteins, RNA and other biomolecules interact with DNA.
The structure of DNA was originally discovered using X-ray crystallography. This involves X-rays scattering off atoms in crystallised arrays of DNA to form a complex pattern of dots on photographic film. Interpreting the images requires complex mathematics to figure out what crystal structure could give rise to the observed patterns.
The new images are much more obvious, as they are a direct picture of the DNA strands, albeit seen with electrons rather than X-ray photons. The trick used by Enzo di Fabrizio at the University of Genoa, Italy, and his team was to snag DNA threads out of a dilute solution and lay them on a bed of nanoscopic silicon pillars.
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